The purpose of the proposed study is to examine the social behavior of peer groups of communally-reared children ranging in age from birth to 30 months, living in the Synanon School. The relative scarcity of research on the social behavior of children of this age range has resulted in a lack of a pre-established or empirically-based behavioral catalogue or ethogram. Such behavior categories will be developed over the course of the proposed three year project. Several different levels of analysis, ranging from descriptions of specific muscle activity to broad and general behaviors will be collected. Observations will be recorded daily on children living in two peer groups: birth-six months and 6-30 months. The general schedule will involve the progressive observation and analysis of: (1) individual motor components of classes of social behavior; (2) sociometric analysis including measures of aggression, submission, cooperation, play, proximity; (3) spectrographic analysis of vocalizations and vocal development; and (4) cinematic analysis of gestural development. Data will be analyzed in several ways in order to achieve different objectives: (1) data relating to specific motor components and elements involved in patterns of locomotion, facial expression, body orientation, and vocalizations will be analyzed using cinematic and spectrographic methods in order to provide the basis for a behavioral catalogue for this age class; (2) data relating to overall social interactions such as attack-flight encounters will be analyzed sociometrically in order to determine the overall pattern and nature of social behaviors; and (3) the daily activity cycles of the various peer groups wll be described.